For C&C...
It looks under exposed a little bit. The white part of the hats is fairly bright, but that makes their skin tones look dark in comparison. Her skin is obviously darker than his, but I think that even his could stand a bit more exposure. Also, there isn't much light in their eyes. Just look at how dark the whites of their eyes are. They do have a catchlight, which is certainly a good thing.

I'm not liking the vignette. Not that I don't think it's a good idea...but it's not evenly applied. Also, they are not centred in the image. Of course, you don't always want to centre your subjects...but in this case, I think that an even space around them, with a uniform vignette....would be much better.